Facile Fabrication of BiF3: Ln (Ln = Gd, Yb, Er)@PVP Nanoparticles for High-Efficiency Computed Tomography Imaging

Abstract

X-ray computed tomography (CT) has been widely used in clinical practice, and contrast agents such as Iohexol are often used to enhance the contrast of CT imaging between normal and diseased tissue. However, such contrast agents can have some toxicity. Thus, new CT contrast agents are urgently needed. Owing to the high atomic number (Z = 83), low cost, good biological safety, and great X-ray attenuation property (5.74 cm2 kg−1 at 100 keV), bismuth has gained great interest from researchers in the field of nano-sized CT contrast agents. Here, we synthesized BiF3: Ln@PVP nanoparticles (NPs) with an average particle size of about 380 nm. After coating them with polyvinylpyrrolidone (PVP), the BiF3: Ln@PVP NPs possessed good stability and great biocompatibility. Meanwhile, compared with the clinical contrast agent Iohexol, BiF3: Ln@PVP NPs showed superior in vitro CT imaging contrast. Subsequently, after in situ injection with BiF3: Ln@PVP NPs, the CT value of the tumor site after the injection was significantly higher than that before the injection (the CT value of the pre-injection and post-injection was 48.9 HU and 194.58 HU, respectively). The morphology of the gastrointestinal (GI) tract can be clearly observed over time after oral administration of BiF3: Ln@PVP NPs. Finally, the BiF3: Ln@PVP NPs were completely discharged from the GI tract of mice within 48 h of oral administration with no obvious damage to the GI tract. In summary, our easily synthesized BiF3: Ln@PVP NPs can be used as a potential clinical contrast agent and may have broad application prospects in CT imaging.

Surface Bio‐engineered Polymeric Nanoparticles

“…The surface functionalization of PNPs enhances their functional performance in imaging in several ways, such as i) enhanced biocompatibility with existing biochemical processes, ii) multimodal imaging capability, and iii) their multiplexing ability to attach signaling or receptor targeting moieties in a single nanocomposite. Surface-modified PNPs have been successfully employed as contrast agents for a number of imaging modalities such as Xray, [44,45,[231][232][233][234] optical imaging, [235][236][237][238][239][240] and magnetic resonance imaging (MRI), [241][242][243][244] as discussed in the following sections.…”

“…[ 231 ] Similarly, bismuth and lanthanides nanoparticles with a polyvinylpyrrolidone (PVP) coating exhibit a superior in vitro X‐ray attenuation than free iohexol commercial contrast agents. [ 44 ] The use of non‐ionic surfactants, such as PEGylated surfactants, during the synthesis method of lipid nanoparticles, has also been explored as a modifying factor for increased stability after intravenous (IV) administration. [ 232 ] In addition, gold is known to exhibit a superior CT imaging efficiency than other elements due to its high atomic number of 79.…”

“…[41,42] Further, surface functionality attained with metallic and non-metallic ionic groups as well as selectively-binding peptides can facilitate the recognition and imaging of tumours or cancerous cells. [43][44][45] Surface functionalization using polymer coatings can also control the duration of circulation in the blood, or half-life, and prevent nanoparticle uptake by the immune system, thus significantly impacting its in vivo fate. [46,47] Using hydrophilic polymers such as polyethylene glycol (PEG) or polysaccharide heparosan (HEP) grafted on the surface of the nanoparticle can provide "stealth" properties and increase their residence time in the blood.…”

Roles of MXenes in biomedical applications: recent developments and prospects

“…Nanomaterials that contain high atomic number elements such as bismuth, cesium, tantalum and tungsten are often considered potential CT imaging materials due to their ability to attenuate X-rays [ 120 ]. The most common clinically approved CT contrast agents, namely, iodine-containing compounds, have been shown to be inappropriate for patients who require repeat CT scans or are at high risk due to their short circulation time in the bloodstream and high toxicity [ 121 , 122 ]. Therefore, the search for CT imaging agents with high atomic number elements and better biocompatibility is a popular direction in the development of CT. Two-dimensional materials such as MXenes have attracted much attention from researchers in the biomedical field due to their unique physicochemical properties and structural characteristics.…”